Iodine is a bluish-black, lustrous solid. Although it is less reactive than the elements above it in group 17 (fluorine, chlorine and bromine) it still forms compounds with many other elements. Although iodine is a non-metal, it displays some metallic properties. When dissolved in chloroform, carbon tetrachloride or carbon disulphide, Iodine yields purple colored solutions. It is barely soluble in water, giving a yellow solution.Iodine is important in medicine, in both radioactive and non-radioactive forms. Iodide and thyroxin, which contains iodine, are used inside the body. A solution containing potassium iodide (KI) and iodine in alcohol is used to disinfect external wounds. Elemental iodine is also used as a disinfectant. Silver iodide is used in photography. Iodine is sometimes added to table salt to prevent thyroid disease. Iodine's other uses include catalysts, animal feeds and printing inks and dyes.